Method for Clarification of Sludge

ABSTRACT

A method for clarifying a sludge, characterized in that a raw waste water is subjected to a solid-liquid separator and then to a primary filtration device, to separate it into a solid material and liquid material, and the resultant liquid treated material is then treated by a process comprising an ozone treatment and a special light ray treatment.

FIELD OF THE INVENTION

The present invention relates to a method for clarification of sludge,for example, wash water from a pigshed, a cowshed or a chicken house, orwaste wash water from a butchery, or waste water from a foods processingfactory, and a clarification equipment thereof.

DESCRIPTION OF THE PRIOR ART

In Japan, from approximately 10 years ago, pollution of ground water isbecoming very serious. Further, pollution of river is also becomingworth. By river environment improving campaign of some volunteer party,several polluted river is becoming to be improved, however, theenvironmental improvement of river is so limited and is not progress aswe please.

In particular, pollution of ground water is a serious problem at presenttime. Nitrogen compound is penetrated into ground water andspontaneously decomposed and forms nitric nitrogen, and we are using theground water as life water.

When nitric nitrogen invades into human body, it spontaneouslydecomposed and forms nitrous nitrogen, and the formed nitrous nitrogeninvades into human's blood, hinders the movement of hemoglobin in bloodand causes a problem of lack of oxygen for a human, further forms acarcinogenic compound. W. H. O. (World Health Organization) regulated astandard value of 1 mgNO₃—N/L. Further, standard value of Japan issettled to same value as W.H.O., however, in Japan, there are fairlynumbers of regions where the value of ground water excess the standard.The main reason of the pollution of the ground water is considered to becaused by agricultural environment.

Agriculture of Japan today is summarized to a problem of excess ofnitrogen. Among the agricultural field, a treatment of excrements ofdomestic animals is the biggest problem. Since the improvement of groundwater pollution is the fundamental object to keep our daily life, it isthe most urgent business for us to develop the most suited means whichcan dissolve said object.

As the conventional method for treatment of excrements of domesticanimals, underground infiltration method, biological treatment andpenetration membrane treatment can be mentioned as main methods. Theunderground infiltration method is same as discharge and is a mainorigin of the ground water pollution. Regarding the biologicaltreatment, funges do not always work through a year. Further, color ofurine does not discolored. Especially, people working in domesticanimals breeding fields, feeds fodder by mixing medicines in it. For thepurpose to protect against infection, water with disinfectant is used aswashing water for cattle shed. Since chemicals are mixing withexcrements, biological treatment can not be a dissolving method. And,regarding the treating method by a penetration membrane, the treatingamount is low and cost for treatment becomes too high, therefore, thismethod can not be used as an actual method. Accordingly, now a day,excrements of domestic animals and waste water after cattle shed washingare discharged on the ground.

In a food processing factory, treatment of waste water has a problem.For example, treatment of waste fluid with coffee dregs which is aby-product of coffee production process or treatment of canned coffeeafter relishing period are not dissolved problems. Especially, in cannedcoffee after relishing period, sugar, antioxidant or flavor arecontained and a method for treatment of these compounds is notaccomplished. Samely, treatment of canned or bottles green tea, red teaor cola are also serious problems. Further, regarding treatment forwaste fluid from Shochu (Japanese spirits) production process, methodfor treatment is quite in the dark. Waste fluid from Sake productionprocess is similar. Some of them are treated by a digestion tank method,which is popular in treatment of waste water from a butchery, however,the capacity of the method is full and can not satisfy demands entirely.

SUMMARY OF THE INVENTION

The present invention is to provide a method for clarification of wastefluid from a cattle shed containing excrements of domestic animals orfrom a food processing process, which are the main origins of groundwater pollution, by a physical method without using chemicals orbiological treatment, further cost for equipment and cost for treatmentcan be reduced.

The essential point of the present invention is a method forclarification of sludge comprising, separating waste fluid-raw solutionto solid and liquid by a solid-liquid separator and a first filtrationapparatus, then treating obtained liquid state treated product by aprocess containing an ozone treatment and a specific ray treatment.

BRIEF ILLUSTRATION OF DRAWINGS

FIG. 1 and FIG. 2 are illustrating views of a treatment of excrementsfrom a pigshed.

FIG. 3 and FIG. 4 are illustrating views of ozone treatment and

FIG. 5 is an illustration view of a ray treating chamber, wherein, (a)is an upright style chamber and (b) is a lateral style chamber.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention will be illustrated more in detail.

In the present invention, the terms of waste fluid and raw solutionindicate a liquid which can be a ringleader of sludge or pollution,specifically said terms indicate waste wash water from cattle-shed,urine of domestic animals, waste water from foods processing or wastewater from a butchery. Further, said terms indicate waste canned coffeeof over relishing period, waste fluid from Shochu production process,waste fluid from Sake production process or waste fluid from all otherbeverage production process. The present invention is a method forclarification of these waste fluid-raw solution to the admittedenvironmental standard value level.

In the present invention, waste fluid-raw solution is separated to solidand liquid by a solid-liquid separator, and separated solid is used asorganic fertilizer or as soil conditioner.

The separated liquid is treated by an ozone treatment by followingconditions. That is, ozone is added to waste fluid-raw solution by3.ONm³/H flow rate at normal temperature. The flow rate of ozone to beadded can be changed according to shape or capacity of a tank. Forexample, by 1.2 Nm³/H, 1.5 Nm³/H-8.0 Nm³/H or by 0.3 Nm³/H-9.0 Nm³/H.For the purpose to improve the effect of ozone reaction, the shape ofreaction tank is designed so as the raw solution to be easily flown byconvection. Further, ozone is added from lower position of the reactiontank, and for the purpose to improve reaction effect, an ozonedischarging nozzle is processed to have star like shape. By processingthe discharging nozzle to have star like shape, ozone bubbles aregranulated more finely and enter between particles of the solution so asto accelerate the ozone reaction. Although the time necessary for ozonetreatment changes according to the amount of the solution to be treated,however, is approximately from 30 to 90 minutes.

Specific ray is irradiated to waste fluid-raw solution which is treatedby ozone treatment. The wavelength of specific ray differs slightlyaccording to power of source, and the irradiation of ultraviolet ray of165 nm-225 nm wavelength or near-ultraviolet ray of 225 nm-350 nm iscarried out. Although irradiation time differs according to the kind ofwaste fluid-raw solution, approximately is from 60 minute to 90 minutes.By this irradiation, various fungi contained in stock solution aresterilized and pigments contained in stock solution are decomposed.

Either ozone treatment or specific ray treatment can be carried outfirst, or ozone treatment or specific ray treatment can be carried outalternatively and repeatably. As a method for specific ray irradiationtreatment, Raw urine liquid is sprayed misty or foggy, or wet wallmethod can be used too. Or, raw urine liquid can be introduced fromlower position of a specific ray treatment tank, which is speciallyprocessed, and can be reacted with irradiation by flowing to upper sideby back eddy method using flowing water of 40 L/min. Further, ozonetreatment or specific ray treatment can be carried out simultaneously byusing a specially processed reaction tank. Aiming to remove decomposedproduct or extracted product formed by ozone treatment or specific raytreatment, liquid after ozone treatment or specific ray treatment ispassed through a filtering apparatus. As a filter, activated carbon,clay, zeolite or sand can be used.

Above mentioned process is shown by a flow sheet in Table 1, and isillustrated more in detail. TABLE 1

-   1. Introduce liquid (waste fluid) which contains solids.-   2. As the first step, said liquid is separated to liquid part and    solid part. As a method for separation, any kind of a centrifuge, a    screen separator or a separation by difference of specific gravity    can be used. By a separator, since complete separation of 100% is    impossible, liquid after separation (waste fluid) is filtrated. As    the method for filtration, filter press, screw press, natural    filtration, suction filtration or vacuum filtration can be used.    Solid part is used as a soil conditioner.-   3. Liquid after solids are removed (waste fluid) is transferred to a    treatment tank. By passing through a specially processed    liquid•ozone gas mixing device, which is equipped to the lower    position of the treatment tank, fine granulation of liquid and ozone    is carried out (refer to FIG. 3). Make the liquid form a suited    state to be decomposed easily by ozone reaction and by next process.    During the reaction, the liquid is stirred by a stirrer equipped to    the top of the tank. When the rotating speed of the stirrer is fixed    to 150 -300 r.p.m., good reaction effect can be accomplished.-   4. Liquid (waste fluid) which is treated by ozone treatment is    transferred to a specific ray treatment chamber. Upright style    chamber or lateral style chamber can be mentioned as a specific ray    treatment chamber, and easier type for use can be selected according    to the place where the chamber is set (refer to FIG. 5). Spiral    shape liquid guide plate of 50 pitches from entrance to exit is set    up to inside of the chamber and the liquid (waste fluid) to be    treated is discharged by rotating. A ray source lamp is set up in    the inside of the chamber. Numbers of the ray source lamp can be    changed according to the quantity of liquid (waste fluid). For    example, when quantity of liquid to be treated is 10 t/day, numbers    of the ray source lamp are 12, when quantity of liquid to be treated    is 20 t/day, numbers of the ray source lamp are 21, that is, can    meet from small quantity to large quantity. The liquid is decomposed    by the ray having specific wavelength mentioned above by rotating    and becomes harmless and is discharged from an outlet.-   5. Liquid (waste fluid) after ray treatment is filtrated. As a    method for filtration, filter press, screw press, natural filtration    or vacuum filtration can be used. As a filter, activated carbon,    activated clay, zeolite or diatomaseous earth can be used.-   6. After all of these processes are over, all standards based on    “Water Pollution Control Law” are cleared and it becomes possible to    discharge the liquid from an outlet. Further, the liquid (waste    fluid) after treated can be used as washing water in a factory.

EXAMPLE

As an Example of the present invention, treatment of excrements from apigshed shown in FIG. 1 and FIG. 2 is illustrated. This example ischaracterized that ozone treatment and specific ray treatment arecarried out simultaneously (end parts of pipe a, b, c and d of FIG. 1are joined with a, b, c and d of FIG. 2).

(1) Raw Excrements Tank

Excrements of a pigshed and wash water from a pigshed are gatheredtogether in a raw excrements tank (1), which is buried in underground.The gathered raw excrements are pumped up and transferred to asolid-liquid separator (2).

(2) Solid-Liquid Separating Apparatus

Liquid transferred from underground stock tank is separated to solidpart and liquid part by a solid-liquid separator (2) which rotates byhigh speed. The solid part is discharged from an outlet (2-1) and isrecovered as a soil conditioner whose nitrogen content is small by aseparated process. The liquid part is discharged from an outlet (2-2)and transported to No. 1 tank (3).

(3) No. 1 Tank

No.1 tank is a tank to be used as a stocker in which liquid part aftersolid-liquid separation is stored.

(4) No. 1 Filtering Apparatus

Aiming to remove small solids which can not be separated by solid-liquidseparating apparatus (2), liquid is passed through No.1 filteringapparatus. The filter used in No. 1 filtering apparatus (4) is zeolite.

(5) No.2 Tank

After passed through No. 1 filtering apparatus, liquid part ofexcrements is recovered in No.2 stock tank (5).

(6) First Treatment Apparatus

Recovered liquid part of excrements in No.2 stock tank (5) istransported to first treatment apparatus (6). First treatment apparatuscarries out ozone treatment and specific ray irradiation treatmentsimultaneously. This first treatment apparatus (6) is consisting of tworeaction tanks which are formed to have an inclination of 35 degreesfrom 3/1 position of the tank to the bottom of tank. Liquid part ofincrements transported from tank No.2 is poured into these 2 tanks andfull the tanks. Specific ray irradiation is carried out simultaneouslywith ozone blowing in. Aiming to improve the effect, the liquid part ofexcrements is stirred. A stirrer is equipped a propeller or a wire blushwhich are processed to have sawteeth shape at a pointed end of it, andgranulate the liquid part of excrements to fine particles. At the bottomof the reaction tank, there is a nozzle to blow in ozone, which isprocessed to have star shape, and ultra fine bubbles of ozone is blownin from the nozzle and is mixed with ultra fine particles of liquid partof excrements. Thus ultra fine bubbles of ozone are mixed with ultrafine particles of liquid part of excrements and thus the reaction isaccelerated.

The purpose of this process is to clarify the raw excrements by 60-70%.

(7) No.2 filtering apparatus (this process and after this process areshown in FIG. 2)

After first treatment is over, the liquid part of raw excrements istransported to No.2 filtering apparatus (7). Impurities which areseparated and extracted at the first treatment (for example, nitrogencompound, phosphorus compound or particles of pigment) are removed.Filter which is used in this process is fine powder of activated carbon.As the other filters which can be used, clay or calcined zeolite can bementioned.

(8) Second treatment apparatus

Liquid part of excrements (7) which have passed through No.2 filteringapparatus is transferred to second treatment apparatus. The shape ofreaction tank of this apparatus is same as that of the first treatmentapparatus. The purpose of this process is to clarify balanced 30-40% ofraw excrements which is not clarified by the first treatment apparatus.Further, the method for treatment is same as that of first treatment.Time for treatment of this process is approximately 60 minutes.

Treating process of first treatment and second treatment are same,however, if the first treatment covers the second treatment, time fortreatment becomes 6 hours longer and clarification ratio is not so good.By dividing to first treatment and second treatment, reaction can becarried out surely, time for treatment can be shortened and treatingcapacity can be improved.

(9) No.3 Filtering Apparatus

After second treatment is over, the liquid part of excrement isfiltrated by No.3 filtering apparatus (9). In this process, impuritieswhich is decomposed and extracted at second treatment is removed. Filterwhich is used in this process is 50% of fine powder of activated carbonand 50% of calcined zeolite. Further, clay or others can be used.

(10) No.3 tank

Tank No.3 (10) is a tank to store the liquid part of excrements whichpassed through No.3 filtering apparatus (9). Since the treated waterstored in this tank is water which satisfies environmental standardvalue, it is possible to discharge the water to river. In the presentinvention, this treated water is reused as washing water for pigshed.

In drawings, (11) indicates an ozone generating device and (12)indicates oxygen generating device. Ozone which is generated in theozone generating device is supplied to first treating apparatus andsecond treating apparatus. Further, (13) is a specific ray device and byray generated in this device, raw excrements in first treating deviceand second treating device are irradiated.

Results after treated by above mentioned treatments are shown in Table2. TABLE 2 Water Pollution before after Items Control Law treatmenttreatment hydrogen ion conc. pH 5.8-8.6 pH 5.1 (18° C.) pH 5.1 (18° C.)pH amount of suspended 200 mg/L  150 mg/L 4.9 mg/L  solid mg/Lbiological oxygen 160 mg/L 8000 mg/L 30 mg/L demand mg/L chemical oxygendemand 160 mg/L 2700 mg/L 20 mg/L mg/L nitrogen content mg/L 120 mg/L2200 mg/L 60 mg/L phosphorous content 16 mg/L  240 mg/L 10 mg/L mg/Lescherichia coli Mg/L 3000 /L not measured not detected

Secondary, one example of ozone treating apparatus to be used in thepresent invention is illustrated according to FIG. 3. As shown in FIG.3, a stirrer 35 is equipped at the center of inside of tank 31, objectto be treated is introduced from lower position of the tank through apipe 33 for example from a ray treatment apparatus and lead to top ofthe tank. Ozone, which is lead through pipe 32 from ozone generatingdevice, is introduced to lower position of the tank and contacts withsaid object to be treated by countercurrent and is treated. And thetreated object is introduced to next second treatment apparatus throughpipe 34.

FIG. 4 shows another example of ozone treating apparatus used in thepresent invention. (a) is front view and (b) is side view. From an inlet41 equipped to one end of cylindrical lateral style tank, object to betreated is introduced and flows in the tank drawing spiral locus towardanother end. In the center of another end there is ozone inlet 42, fromwhere ozone is introduced, contacts with the object to be treated andtreated product 43 is discharged from outlet 43 located at the center ofthe tank.

FIG. 5 is an illustration view of a ray treating chamber, wherein, (a)is an upright style chamber and (b) is a lateral style chamber. As shownin FIG. 5, in the chamber, ray lamps 51 are arranged parallel and amongeach ray lamps a guide plate 53 is arranged spirally. Object liquid tobe treated is introduced from entrance 52, flown along with the guideplate 53 and irradiated by ray lamp 51 and is discharged from outlet 54.Then is transported to next process.

APPLICABILITY FOR INDUSTRIAL USE

As mentioned above, since the present invention does not use chemicalsat all, secondary waste product is not formed. Further, sludge isclarified by physical treatment, that is, ozone treatment and specificray treatment, equipment investment and treatment cost can be reduced.

1. A method for clarification of sludge comprising, separating wastefluid-raw solution to solid and liquid by a solid-liquid separator and afirst filtration apparatus, and treating the obtained liquid stateproduct by an ozone treatment and a specific ray treatmentsimultaneously.
 2. The method for clarification of sludge of claim 1,wherein the specific ray is a ray which has wavelength of the range fromultraviolet ray region to near-ultraviolet ray region.
 3. The method forclarification of sludge of claim 1, wherein waste fluid-raw solution iswash water from a pigshed, a cowshed or a chicken house, or waste washwater from a butchery, or processed foods liquid of over relishingperiod, such as coffee, Sake or Shochu.
 4. The method for clarificationof sludge according to claim 1, wherein solid obtained by a solid-liquidseparator and a first filtration apparatus is used as a soilconditioner.
 5. An apparatus for clarification of sludge comprising, aclarification equipment of sludge consisting of a solid-liquid separatorand a first filtration apparatus which separates waste fluid-rawsolution, an ozone treating apparatus which carry out ozone treatment ofthe obtained liquid state product and a specific ray treatment apparatuswhich irradiates specific ray, wherein, said specific ray treatmentapparatus comprises a guide plate so as the liquid state treated productto flow spirally between specific ray lamps arranged in parallel.